When a patient is in need of being connected to a breath delivery system, e.g. during an operation or when in a coma, or for any other reason is in need of assisted breathing, the patient is attached to the system. When a ventilator is operating in a volume control mode, a prescribed tidal volume is specified for delivery to the patient. However, the pressure in the patient's lungs in increases when gas is introduced by the ventilator and this can only happen if the pressure in the tubing system is greater than the pressure in the lungs. Thus the tubing system must be pressurized in order to deliver gas to the patient lungs. The process of pressurization requires that a volume of gas be delivered to the tubing system. Therefore, to deliver a predetermined amount of gas to the patient's lungs requires the ventilator to deliver that predetermined amount of gas plus the volume of gas required to pressurize the tubing system to the levels required for gas to be transferred from the tubing system to the patient's lungs.
U.S. Pat. No. 6,142,150 discloses one type of gas delivery concept.
The inventor of the present invention has appreciated that an improved breath delivery system is of benefit, and has in consequence devised the present invention.